The Battle of Gilly was fought on the morning of the 15th against the Prussian rearguard and the advancing French Army of the North. The Prussians were pushed back, and the French Army crossed the Sambre River to fight the main Prussian army at Ligny the next day. 

Once downloaded, you'll have full access to an 18x24 map in 2 versions. a full-scale version that you can print on an 18x24 poster print, and a tiled version. The latter makes it available for people who don't want to make a big investment in printing. Its 8 sheets on US legal-sized paper, when printed and assembed creates a 18x24 map of the battle. You will need scissors or a craft knife, glue, appropriate paper and some stiffer card for bassing such as cardboard.